The points indicator is coupled to the points set via a ground rod configuration and hand tumbler.
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When the points are operated by the hand tumbler, the indicator lever slide lifts the vertical plunger clear of the detector slides and allows the detector slide to move across as the switches move to the other position.
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Manual operation
For shunting purposes or opposing train movements, the points can be operated in the conventional manner with a hand tumbler.
http://www.actom.co.za/pages/Actom-Divisions/products-view-m...

We know that the hand points are operated by different levers. One of them is "TUMBLER POINT" and " SPRING LOADED POINT".Please defined the "TUMBLER POINT" and "SPRING LOADED POINT"
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Tumbler and spring loaded are the form of levers with which the points are hand operated.
In tumbler there is a weight named tumbler connected at upper end of the lever. While operating the point, the lever(fitted with tumbler) has to be lifted up, directed towards direction of operation and left. The point is set by force exerted by tumbler (minimum human force involved).

The second type has a simple level which also functions on the same lines but human force has to be applied intil the complete operation.
http://iricen.indianrailways.gov.in/IRICEN1/modules.php?name...

These types are designated
« aiguille à contrepoids » = “weighted points”,
« aiguille à ressort » = “spring points”,
« aiguille á main, ~ manoeuvée à main » = “points operated by hand, hand-operated switch”.
(UIC, Lexique général des termes ferroviaires)

Cheville Tige de métal munie d'une poignée que l'on enfonce dans la rotule du levier auxiliaire d'une aiguille à contrepoids tournant.
http://plm1950.msts.free.fr/rail/Vocabulaire.html

Suggestion

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Note added at 4 jours (2014-11-20 18:02:51 GMT)
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C'est une sorte d'interrupteur à levier. Dans le jargon des chemins de fer, on laisse "tumbler".